Combined support and ground clip for heater elements

ABSTRACT

A combined supporting and electrical grounding structure is incorporated in a baseboard electric heater. The tube of a finand-tube elongated heating element is supported on a bracket. The tube is anchored firmly to the bracket by an inverted-U locking plate that has a pair of legs with offset portions extending across an edge of the support bracket. Adjacent to that edge of the bracket there is a slot into which a screwdriver can be inserted and twisted for deforming the bracket, to tighten the locking plate firmly.

United States Patent Inventor William A. Bollinger Augusta, S.C

Appl. No. 883,106

Filed Dec. 8, 1969 Patented Dec. 14, 1971 Assignee Federal PacificElectric Company Newark, NJ.

COMBINED SUPPORT AND GROUND CLIP FOR HEATER ELEMENTS 12 Claims, 9Drawing Figs.

US. Cl 219/365, 219/366, 219/375, 219/536, 248/65, 338/316 Int. Cl F24h7/00 Field of Search 219/365,

[56] References Cited UNITED STATES PATENTS 1,452,993 4/1923 Wack248/300 2,062,466 12/1936 Marr 219/365 2,250,280 7/1941 Starbird l74/401 3,510,628 5/1970 Zahaykevich 174/65 Primary Examiner-J. V. TruheAssistant Examiner-G. R. Peterson Att0rney-Paul S. Martin ABSTRACT: Acombined supporting and electrical grounding structure is incorporatedin a baseboard electric heater. The tube of a fin-and-tube elongatedheating element is supported on a bracket. The tube is anchored firmlyto the bracket by an inverted-U locking plate that has a pair of legswith offset portions extending across an edge of the support bracket.Adjacent to that edge of the bracket there is a slot into which a'screwdriver can be inserted and twisted for deforming the bracket, totighten the locking plate firmly. 7

Minn! PATENTEDBEBMIHYI 3 627 9 4 SHEET 1 OF 2 INVENTOR WILL/AM AZBOL/JNGEQ ATTORNEY PATENTED DEC 1 4 ml sum 2 m 2 INVENTOR WILL IAMA.BOLL/NGE'R BY j /2 :0 ),M1- ATTORNEY COMBINED SUPPORT AND GROUND CLIPFOR HEATER ELEMENTS This invention relates to comfort space heaters andthe like and more particularly to means for mounting the heating elementin such apparatus.

So-called comfort space heaters are widely used for heating rooms inoffices, homes, and so on. A popular type of comfort space heater has anelongated heat-exchange element in an elongated enclosure. The heaterhas a low profile so that it may be used along a wall in lieu of thenormal baseboard molding. Such baseboard heaters" are particularlypopular. Electric baseboard heaters require provision for the expansionand contraction of the heating element which occurs during its cycles ofheating when energized and cooling when deenergized. The expansion andcontraction of the heating element is a source of difficulty in the caseof electric heaters since the National Electric Code requires theheating element to be connected to an electrical ground. It is an objectof this invention to provide improved, economical means for fixing theheating element of a space heater in position in its enclosure. It isyet another object of this invention to provide improved means forelectrically grounding the electric element of a baseboard heater.

The heating element may be fabricated in at least two versions. Oneversion has a single tubular resistor and another has dual tubularresistors. In the dual-tube form, a series of heatdissipating fins aresecured to two longitudinally extending parallel sheathed resistanceheating elements. The resistance wire is encased in a metal tube that isfilled with a compacted granular insulation such as magnesium oxide.Rotation of the dual-tube heating element about its longitudinal axis iseasily prevented by the mounting brackets. However, a problem arosewhere the single tube was employed, in that there is a tendency of theheating element to rotate about its longitudinal axis, during shipmentand during installation and even when in use over long periods of time.Rotation of the element can cause the fins to touch the enclosure. Finstouching the enclosure cause noisy operation of the heater during theexpansion and contraction of the heating element as the fins drag acrossthe backwall or front cover of the enclosure. An

object of this invention resides in providing an improved mounting meansfor electrical heating elements to prevent such rotation of the heatingelement.

The foregoing objects and advantages are achieved in the illustrativeembodiment of the invention described in detail below and shown in theaccompanying drawings. In that embodiment, a heat-exchange unitcomprises an elongated electric heating element bearing transverse fins.The mounting means for the heating element has a support bracket for theelement and a securing plate cooperating with the bracket for preventingrelative movement between the bracket and the heating element. Thebracket has a notch whose sides constitutes leg portions spaced apart toreceive the heating element. The securing plate also includes a pair ofspaced legs connected together by a bridging portion, forming aninverted generally U-shaped member. The heating element is trapped andfixed in position in the notch of the bracket and the oppositelydirected U-shaped securing plate. Formations on the bracket and thesecuring plate cooperate with each other to develop a tight grip on theheating element. A pair of sharp comers in the gripping edges providesecure grounding and prevent rotation of the heating element.

For a better understanding of the invention in its various aspects,reference is made to the following description of the illustrativeembodiment, and to the accompanying drawings showing a presentlypreferred embodiment of the invention. In those drawings:

FIG. 1 is a front elevation of an electric baseboard heater with thefront cover removed for purposes of illustration;

FIGS. 2, 3 and 4 are fragmentary front views of portions of thebaseboard space heater of FIG. I, identified by the circled areas ofFIG. 1, on a greatly enlarged scale;

FIG. 5 is a cross section at the line 5-5 of FIG. 3, omitting theenclosure and showing the front cover in phantom lines;

FIG. 6 is a lateral view of a securing plate or clip shown in theassembly of FIG. 5;

FIG. 7 is an edgewise view of the securing plate or clip of FIG. 6;

FIG. 8 is a fragmentary top view partly in cross section along line 8-8of FIG. 3; and

FIG. 9 is a fragmentary cross-sectional view along the line 9-9 of FIG.4.

Referring to the drawing, an illustrative embodiment of the invention asshown is an electric baseboard heater 20. Sheet metal enclosure 22 ofthe baseboard heater has a rear wall 24 and end walls 26 and 28. A frontcover 30 (shown in phantom lines in FIG. 5) extends from one end wall tothe other in front of heater element 32 and the end terminal boxes 34,36. The terminal boxes contain the connections between the internalwiring (not shown) of the heater and the external power circuit wiring.For an illustration of such wiring reference may be made to pendingZahaykevich application Ser. No. 647,976, assigned to the assignee ofthe present invention.

The heat-exchange element 32 includes a diagrammatically shown centralresistance wire 38 which is surrounded by compacted granular insulation40 within a tube 42. Advantageously, the resistance wire 38 is Nichrome,the granular insulation is magnesium oxide and the tube is aluminum. Aplurality of fins 44 are mounted on the tube. Each fin has an extendedneck 46 that tightly fits the tube, and laterally extending fin portions48 that have formed ends 50. The fins are staked at 52 to the tube atdiametrically opposed points to prevent relative lengthwise androtational movement on the tube.

The heat-exchange element 32 is supported and positioned within theenclosure 22 by a pair of end brackets 54, 56 and a center bracket 58.The end brackets 54, 56 form part of the respective end terminal boxes34, 36. The element 32 is fixed in place in the enclosure by the centerbracket 58, as will be explained in detail below. The ends of theelement 32 are free to move longitudinally relative to the brackets 54,56 as it expands'and contracts in use due to heating and cooling. Theend portions 32a, 32b are restrained against undue lateral movement byretainers 60 (FIGS. 2, 4 and 9) having a loose fit or a sliding fit ontube 42. Bracket portions 61 support retainers 60.

Referring to FIGS. 3 and 5 to 8, the center bracket 58 of sheet metalincludes a base portion 581: secured to the rear wall 24 of theenclosure. Upper and lower arms 58b, 580 are spaced apart, and theyextend perpendicularly outwardly from base 58a. Lower arm 58c has aplate portion that is notched at the top, to define a pair of upwardlyextending legs 58d, 58c, connected by a bight 58f. The legs closelyflank opposite sides of the heat-exchange element between an adjacentpair of fins. In FIG. 5 the legs engage the extruded portion 46 of oneof the fins 44 that overlies the tube 42. If desired, the legs can bemade to engage the tube 42 directly, by shortening the neck 46 of one ofthe fins. The heater element is held in position by securing means inthe form of a generally flat locking plate or clip 62 that has a deepnotch so as to have a pair of legs 62a, 62b connected together at abight 62c. Plate 62 is an inverted generally U-shaped part. Each leg62a, 62b has a transverse or offset end portion 62d, 62c having a detentportion 62f, 62g that is bent upward for locking engagement with thelower edge 58g of bracket arm 580. The bight portion 620 has a pair ofspaced sharp projections 62h which forcible engage and penetrate intothe surface of the heater element 32. Bracket arm 580 has a slot 581'formed adjacent to and generally parallel to edge portion 58 to providea deformable part 58j for purposes described below. Lateral edges 58h atthe ends of edge portion 583 guard against any tendency of the legs 62aand 62b to spread.

In manufacturing the heater 20, the enclosure 22 is substantiallycompleted before the heat-exchange element 32 is installed. At thattime, the end brackets 54, 56 and center bracket 58 have been secured tothe rear wall 24 of the enclosure. The heat-exchange element 32 isshifted laterally into the space between the upper and lower legs 58b,58c of the center bracket and then lowered into position between legs58d, 58e. The legs enter the space between two successive fins. The tuberests against the bight 58f. Locking plate or clip 62 is next slid intoplace between the fins, and then it is moved laterally against bracket58. The transverse or ofiset portions of the legs are small enough toenter the space between two adjacent fins even when the bracket 58 isalready in that space. The clip 62 is moved downward and comes to restwith the bight projections 62h engaging the heat'exchange element 32.The leg ends 62d, 62e are then snapped over the bracket edge 58g whichsnaps past detents 62f, 62g. At this point the heater element 32 istrapped. However, it may still be rotated about its longitudinal axisfor final adjustment. In order to lock the heater element securely inposition a tool such as a blade of a screw driver is inserted in theslot 581', and twisted. The twisting action deforms portion 58] to movefrom its dotted position of FIG. 5 to the solid line position. Thedeformation of bracket portion 58j. causes the sharp corners 62h of thebight portion of the clip to drive into the heater element 32.Advantageously, the clip and bracket are made of galvanized steel sothat forceful engagement may be maintained between the assembled parts.The heat-exchange element is tightly gripped between the bights 62c and58]: of the locking plate 62 and the supporting portion of bracket arm580. so that bights 58c and 680, h are gripping portions. A tight gripis established by cooperation of portions 58j of the bracket withportions 62f and 62g of the locking plate or clip 62. Between thegripping portion 58]" of the bracket and its cooperating" portion 58j,there is an intermediate portion; and likewise locking plate 62 has anintermediate portion between its gripping portion 62h and itscooperating" portion(s) 62f, 62g; and these two intermediate portionsare face-to-face and generally parallel to the fins between which thebracket extends. These intermediate portions provide separation betweenthe heater-gripping portions located between the fins and thecooperating portions of the locking plate and the bracket located clearof the fins (see FIG. 5) so that slot 581' and the leg ends 62d and .622are in a position of clearance for easy handling. Sharp corners 62hindent the engaged neck 46 of the fins and they also indent tube 42.Where the neck 46 is soft and thin, corners 62h can even penetrate theneck 46 and thus make direct contact to tube 42. Furthermore, ofi'setparts 62d and We make secure metal-to-metal contact to lower arm 58c ofbracket 58 which, in turn, has a fastening that provides mechanical andelectrical connection to the enclosure wall 24.

The end retainers 60 are next secured to parts 61 of the respective endbrackets 54, 56, and electrical connections are made to the ends of theresistance wire 38.

The-foregoing construction provides an excellent, dependablemetal-to-metal connection between the heat-exchange element 32 and thebracket 58 to assure proper electrical grounding, and the sameconstruction fixes the heating element against rotation. Theheat-exchange element is free to expand and contract, but it is captiveagainst rotation about its longitudinal axis. The location of slot Slibelow the level of the fins makes for easy access to that point for atool to deform strip 58] downward in tightening the grip of the lockingplate and the supporting plate against the heating element 32.

While only one embodiment of the invention has been shown and describedin detail it will be recognized by those skilled in the art that variouschanges and modifications may be made herein without departing from thespirit and scope of the invention.

What is claimed is:

l. A space heater including a heat-exchange unit comprising an elongatedheating element including an elongated heating tube bearing a series oftransverse heat-exchange fins, an enclosure for said heat-exchange unit,and means for supporting said heat-exchange unit in said enclosure, saidsupporting means including a bracket secured to said enclosure andhaving a plate portion extending between two of said fins, and a lockingplate having an intermediate portion in face-to-face confrontation withsaid plate portion, and essentially parallel to said fins, said bracketand said locking plate having respective portions gripping oppositesides of said elongated tube and having mutually cooperating means atone of said opposite sides of said elongated tube for causing saidgripping portionsto grip said elongated tube, and said plate portion ofsaid bracket extending between and interconnecting said gripping portionand said cooperating means of the bracket, and said intermediate portionof said locking plate extending between and interconnecting saidgripping portion and said cooperating means of the locking plate, fordisposing said cooperating means at a location spaced substantially fromsaid elongated heater tube.

2. A space heater in accordance with claim 1 wherein at least one ofsaid gripping portions is part of a formation that includes a pair oflegs closely straddling said elongated tube.

3. A space heater in accordance with claim 1 wherein each of saidgripping portions is part of a fonnation that includes a pair of legsstraddling said elongated heating tube.

4. A space heater in accordance with claim 1 wherein said elongatedheating tube contains an insulated electric resistance wire, and whereinat least one of said gripping portions includes at least one sharpprojection of metal forced into electrical contact with said elongatedheating element by said cooperating means.

5. A space heater including a heat-exchange unit comprising an elongatedheating element including an elongated heating tube bearing a series oftransverse heat-exchange fins, an enclosure for said heat-exchange unit,and means for supporting said heat-exchange unit in said enclosure, saidsupporting means including a bracket secured to said enclosure andhaving a plate portion extending between said fins, and a locking plateconfronting said plate portion, said bracket and said locking platehaving respective portions gripping opposite sides of said elongatedheating tube and having cooperating portions at the side of saidelongated heating tube remote from the gripping portion of said lockingplate for causing said gripping portions to grip said elongated heatingtube, said locking plate including at least one leg having a laterallyoffset part extending across an edge portion of said bracket, saidbracket having an elongated opening formed therein adjacent to andgenerally parallel to said edge portion so as to define a strip, saidstrip and said offset portion constituting said cooperating portions,and said strip being deformed for causing said gripping portions to gripsaid elongated heating tube as aforesaid. I

6. A space heater in accordance with claim I wherein said locking plateis an inverted generally U-shaped member including a pair of legsclosely flanking said elongated heating tube and connected by a bridgingportion constituting said gripping portion of said locking plate, theextremities of said legs being offset across an edge portion of saidbracket, said ofi'set portions of said legs and said edge portion ofsaid bracket constituting said cooperating means for causing saidgripping portions to grip said elongated heating tube.

7. A space heater including a heat-exchange unit comprising an elongatedheating element including an elongated heating tube bearing a series oftransverse heat-exchange fins, an enclosure for said heat-exchange unit,and means for supporting said heat-exchange unit in said enclosure, saidsupporting means including a bracket secured to said enclosure andhaving a plate portion extending between said tins, and a locking plateconfronting said plate portion, said bracket and said locking platehaving respective portions gripping opposite sides of said elongatedheating tube and having cooperating portions at the side of saidelongated heating tube remote from the gripping portion of said lockingplate for causing said gripping portions to grip said elongated heatingtube, said gripping portion of said bracket being the bottom portion ofa notch having lateral edges closely flanking said elongated heatingtube, and said locking plate including a pair of legs flanking saidelongated heating tube and extending downward from a gripping portion ofsaid locking plate, and said leg portions having offset extremitiesextending across an edge portion of said bracket, said bracket having anelongated opening extending adjacent to and generally parallel to saidedge portion so as to define a strip, said offset portions and saidstrip constitutes said cooperating portions of said bracket and saidlocking plate, and said strip being deformed for causing said grippingportions to grip said elongated heating tube as aforesaid.

8. A space heater in accordance with claim 7 wherein said edge portionincludes lateral formations obstructing laterally outward spread of saidlegs at said offset portions and wherein said strip is bowed downwardbetween said offset portions.

9. A space heater in accordance with claim 5, said strip having endsintegral with the remainder of the bracket, said strip being deformed inthe direction away from said elongated heating tube and against saidofiset portion so that said strip and said offset portion constitutesaid cooperating portions causing said gripping means to .grip saidelongated heating tube.

10. A space heater including a heat-exchange unit comprising anelongated electric heating element having a metal tube comprising aninsulated resistance wire and transverse heatexchange fins on said metaltube, an enclosure for said heatexchange unit, and means for supportingand electrically grounding said heat-exchange unit, said supporting andgrounding means including a pair of mutually confronting metal platesextending between a pair of said fins and having oppositely directednotch formations gripping said tube, one of said metal plates beingsecured to said enclosure, a first one of said metal plates having anoffset portion extending across an edge portion of the second of saidmetal plates at the side of the gripped tube remote from said grippingformation of said first metal plate, said second metal plate having anelongated opening therein extending transverse to an imaginary'linebetween the gripping portion and the offset portion of said first metalplate and said opening extending adjacent to and generally parallel tosaid edge portion thereby defining a strip whose ends extend integrallyfrom said second plate and said strip bearing tightly against saidoverhanging portion for maintaining a tight grip of said grippingportion against said tube.

11. A space heater in accordance with claim 10 wherein at least one ofsaid plates has at least one sharp projection at a gripping portionthereof embedded in said metal tube.

12. A space heater including a heat-exchange unit comprising anelongated heating element including an elongated electric heating tubebearing a series of transverse heat-exchange fins, an enclosure for saidheat-exchange unit, and means for electrically grounding and forsupporting said heat-exchange unit in said enclosure, said supportingmeans including a metal bracket member secured to said enclosure andhaving a portion extending into the space between two successive fins ofsaid series of fins, and a locking member extending into said space,said members having respective portions gripping opposite sides of saidelongated heating element and having cooperating portions outside saidspace between said two successive fins causing forcible grip of saidelongated heating tube by said gripping portions, one of said membershaving an offset part against an edge portion of the other of saidmembers and one of said members having a slot adjacent said edgeportion, the material of the latter member between said slot and saidoffset part being deformed against said offset part, the deformed partand the offset part constituting said cooperating portions.

I I t

1. A space heater including a heat-exchange unit comprising an elongated heating element including an elongated heating tube bearing a series of transverse heat-exchange fins, an enclosure for said heat-exchange unit, and means for supporting said heatexchange unit in said enclosure, said supporting means including a bracket secured to said enclosure and having a plate portion extending between two of said fins, and a locking plate having an intermediate portion in face-to-face confrontation with said plate portion, and essentially parallel to said fins, said bracket and said locking plate having respective portions gripping opposite sides of said elongated tube and having mutually cooperating means at one of said opposite sides of said elongated tube for causing said gripping portions to grip said elongated tube, and said plate portion of said bracket extending between and interconnecting said gripping portion and said cooperating means of the bracket, and said intermediate portion of said locking plate extending between and interconnecting said gripping portion and said cooperating means of the locking plate, for disposing said cooperating means at a location spaced substantially from said elongated heater tube.
 2. A space heater in accordance with claim 1 wherein at least one of said gripping portions is part of a formation that includes a pair of legs closely straddling said elongated tube.
 3. A space heater in accordance with claim 1 wherein each of said gripping portions is part of a formation that includes a pair of legs straddling said elongated heating tube.
 4. A space heater in accordance with claim 1 wherein said elongated heating tube contains an insulated electric resistance wire, and wherein at least one of said gripping portions includes at least one sharp projection of metal forced into electrical contact with said elongated heating element by said cooperating means.
 5. A space heater including a heat-exchange unit comprising an elongated heating element including an elongated heating tube bearing a series of transverse heat-exchange fins, an enclosure for said heat-exchange unit, and mEans for supporting said heat-exchange unit in said enclosure, said supporting means including a bracket secured to said enclosure and having a plate portion extending between said fins, and a locking plate confronting said plate portion, said bracket and said locking plate having respective portions gripping opposite sides of said elongated heating tube and having cooperating portions at the side of said elongated heating tube remote from the gripping portion of said locking plate for causing said gripping portions to grip said elongated heating tube, said locking plate including at least one leg having a laterally offset part extending across an edge portion of said bracket, said bracket having an elongated opening formed therein adjacent to and generally parallel to said edge portion so as to define a strip, said strip and said offset portion constituting said cooperating portions, and said strip being deformed for causing said gripping portions to grip said elongated heating tube as aforesaid.
 6. A space heater in accordance with claim 1 wherein said locking plate is an inverted generally U-shaped member including a pair of legs closely flanking said elongated heating tube and connected by a bridging portion constituting said gripping portion of said locking plate, the extremities of said legs being offset across an edge portion of said bracket, said offset portions of said legs and said edge portion of said bracket constituting said cooperating means for causing said gripping portions to grip said elongated heating tube.
 7. A space heater including a heat-exchange unit comprising an elongated heating element including an elongated heating tube bearing a series of transverse heat-exchange fins, an enclosure for said heat-exchange unit, and means for supporting said heat-exchange unit in said enclosure, said supporting means including a bracket secured to said enclosure and having a plate portion extending between said fins, and a locking plate confronting said plate portion, said bracket and said locking plate having respective portions gripping opposite sides of said elongated heating tube and having cooperating portions at the side of said elongated heating tube remote from the gripping portion of said locking plate for causing said gripping portions to grip said elongated heating tube, said gripping portion of said bracket being the bottom portion of a notch having lateral edges closely flanking said elongated heating tube, and said locking plate including a pair of legs flanking said elongated heating tube and extending downward from a gripping portion of said locking plate, and said leg portions having offset extremities extending across an edge portion of said bracket, said bracket having an elongated opening extending adjacent to and generally parallel to said edge portion so as to define a strip, said offset portions and said strip constitutes said cooperating portions of said bracket and said locking plate, and said strip being deformed for causing said gripping portions to grip said elongated heating tube as aforesaid.
 8. A space heater in accordance with claim 7 wherein said edge portion includes lateral formations obstructing laterally outward spread of said legs at said offset portions and wherein said strip is bowed downward between said offset portions.
 9. A space heater in accordance with claim 5, said strip having ends integral with the remainder of the bracket, said strip being deformed in the direction away from said elongated heating tube and against said offset portion so that said strip and said offset portion constitute said cooperating portions causing said gripping means to grip said elongated heating tube.
 10. A space heater including a heat-exchange unit comprising an elongated electric heating element having a metal tube comprising an insulated resistance wire and transverse heat-exchange fins on said metal tube, an enclosure for said heat-exchange unit, and means for supporting and electrically grounding said heat-exchange unit, saiD supporting and grounding means including a pair of mutually confronting metal plates extending between a pair of said fins and having oppositely directed notch formations gripping said tube, one of said metal plates being secured to said enclosure, a first one of said metal plates having an offset portion extending across an edge portion of the second of said metal plates at the side of the gripped tube remote from said gripping formation of said first metal plate, said second metal plate having an elongated opening therein extending transverse to an imaginary line between the gripping portion and the offset portion of said first metal plate and said opening extending adjacent to and generally parallel to said edge portion thereby defining a strip whose ends extend integrally from said second plate and said strip bearing tightly against said overhanging portion for maintaining a tight grip of said gripping portion against said tube.
 11. A space heater in accordance with claim 10 wherein at least one of said plates has at least one sharp projection at a gripping portion thereof embedded in said metal tube.
 12. A space heater including a heat-exchange unit comprising an elongated heating element including an elongated electric heating tube bearing a series of transverse heat-exchange fins, an enclosure for said heat-exchange unit, and means for electrically grounding and for supporting said heat-exchange unit in said enclosure, said supporting means including a metal bracket member secured to said enclosure and having a portion extending into the space between two successive fins of said series of fins, and a locking member extending into said space, said members having respective portions gripping opposite sides of said elongated heating element and having cooperating portions outside said space between said two successive fins causing forcible grip of said elongated heating tube by said gripping portions, one of said members having an offset part against an edge portion of the other of said members and one of said members having a slot adjacent said edge portion, the material of the latter member between said slot and said offset part being deformed against said offset part, the deformed part and the offset part constituting said cooperating portions. 